Oil-switch.



E. H. JACOBS.

OIL SWITCH.

APPLICATION FILED JUNE 1e, 1913y 1,1 33,032. Patented Mar. 23, 1915.

Witnesses: Inventor ETTweStHJaCObS,

UNITED 'sTATEs PATENT oEEieE.

ERNEST H. JACOBS, OF SCHENECTADY, NEW lYORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

OIL-SWITCH Application led .Tune 18;, 1913.7. Serial N o. 774,496.

To all whom it may concern:

Be it known that I, ERNEST H. JACOBS, a citizen' ofthe United States, residing at Schenectady', county of Schenectady, State of New York, have invented certain new and useful 'Improvements in Oil-Switches, of which the following is a specification.

Myinvention relates to electric switches and more particularly to switches used to control circuits which carry great amounts of energy.

The object of my invention is to provide a simple, compact and eihcient switch which has great rupturing capacity' and in which current limiting means, suchas resistance, automatically connected in series withV the circuitin a very simple and reliable manner during the openingo the switch, in order to decrease the flow of energy to be interruptedk when the switch finally opens the circuit. Resistance has heretofore been introduced into the circuit as the switch opens, but usually by`means ot'complicated and objectionable mechanism. In accordance with my invention the resista-ncereouired to `decrease the energy loss to the desired extent is inthe oilv vesselv of the switch, preferably in` thermal relation to the oil .so that a great deal of energy can be absorbed 'by the resistance without the temperature rising to a dangerous point. The preferred construction is such lthat when the switch is closed the circuit through it docs not include the oil vessel through a path of low resistance, but as the switch opens, the resistance of the oil vessel is automatically introduced yinto the circuit in series with the switch to reduce the amount of the energy which must be dissipated in the disruptive discharge in the oil vessel during the opening of the circuit.

My invention also embodies other details ofstr-ucture which will be more specifically pointed out in the claims appended hereto.

'The features of construction and mode of operation ofthe preferred form of my invention will be best understood -by reference te the following description taken in connection with the accompanying drawing which represents, in elevation and partly inseotiom an oil switch -embodving one form of my invention.

My invention may he embodied in other switches of many different forms but the form I have shown, for purposes of illustration, is a double break oil switch. The line terminals l and 2 are in conductive relation with the two metallic casings or oil vessels 3 and t respectively. These oil vessels are made of iron or of any other suitable material which offers. a suiciently high resistance to the passage of an yelectric current and are mounted in any convenient way, for example, upon insulators 5. and 6 respectively. The Vessels are partially filled with oil to the level. shown-by the dotted line. The two oil vessels 3 and 4 havecovers 7 and 8, respectively, which render the vessels substantially closed.` At their upper end and projecting into thc vessels 3 and 4, through their respective insulating bushings, 9 and 10, are movable contacts 1l and 12. These contacts cooperate with fixed con- `tacts at the bottom of theirrespective oil vessels 3 and 4. Only one of the fixed contacts is shown in the drawing, namely the contact 13 which cooperates with the movable contact 12.v The fixed contacts mounted within their respective oil vessels beneath the surface of the oil and the movable contacts 11 and 12, act as auxiliary or shunt contacts by which the circuit though the switch is finally broken. The auxiliary contacts are so arranged in relation to their respective oil vessels that the fiow of current in the oil vessel at kany given instant is opposite in direction from the flow of current at the same given instant through the auxiliary contacts. By this arrangement each fixed contact forms a magnetic loop with its respective oil vessel, and a strong magnetic field is set up around each fixed contact., which serves to `quench the arc which may be formed when the auxiliary contacts separate.

The contacts 11 and 12 are mounted upon and electrically connected by a. metallic yoke or bridging member 14 which is actuated in any suitable manner to simultaneously lower or raise the movable'contacts and thereby make or break the auxiliary or shunt circuit. The yoke or bridging member 14 also carries the main movable contacts 15 and 16, which cooperate with the main stationary contacts 17 and 18 mounted upon the upper end of theoil vessels 3 and 4, respectively, and in conductive relation therewith.

The operation of the device is as follows: When the switch is closed the main movable contacts l5 and 16 are in engagement with Patented Mar. es, 1915.

their respective main stationary contacts 17 and 18, and the contacts 11 and 12 are in engagement with their respective auxiliary contacts in the oil vessels 3 and 1. Practically all of the current flows from line terminal 1 through the low resistance path offered by the covers of the oil vessels, through the main contacts and the yoke 14, to the other line terminal 2. \Vhen the switch begins to open, the main movable contacts 15 and 16 separate from their respective stationary contacts 17 and 18 before the movable shunt contacts 11 and l2 sep arate from the fixed shunt contacts in the bottom of the oil vessels 3 and yl; that is, the main contacts separate while the auxiliary contacts are still in engagement. 'hen this condition occurs, the circuit from terminal 1. to terminal 2 through the main contacts is interrupted, and all the current must flow through the shunt circuit from terminal 1 through the oil vessel 3 to contact 11, through yoke 1-1, to contact 12 and through the oil vessel 4, to terminal 2. By this arrangement, the main contacts normally complete a circuit of low resistance around the oil vessels, but during the opening of the switch the high resistance offered `by the oil vessels 3 and l, connected in series, is automatically included in the circuit before the circuit is finally broken by the switch. As the switch opens further the auxiliary contacts finally separate and break the circuit. rlhe arc formed is quickly quenched by the strong magnetic fields surrounding the shunt contacts and by the oil. No arc forms when the main contacts separate, for there is still a path for the electric current through the switch, but when the auxiliary contacts separate, the circuit is opened and the current through the switch broken. By including automatically the resistance of the. vessels 3 and 1 in the circuit through the switch, when the main contacts separate, the energy of the disruptive discharge produced as the circuit is finally broken by the auxiliary contacts, is greatly reduced. As a result the action of the magnetic field to quench the arc is rendered very effective, the capacity of the switch increased, and the harm likely to occur from theexcessive arcing beneath the surface of the oil is greatly reduced.

Many changes may be made in the form in which my invent'roriis embodied, and as the switch I have shown is merely illustrative of one form of the invention, I do not Wish to be restricted to the precise form shown and described but intend to cover all changes and modifications Within the spirit and scope of my invention, as set forth in the appended claims.

lVhat I claim as new and desire to secure by 'Letters Patent of the United States, is

1. In an electric switch, the combination of a vessel containing oil and having a high resistance portion, contacts adapted when in engagement to close a low resistance circuit in parallel with said portion of said vessel, and means for automatically including said portion of said vessel in said circuit as said main contacts are separated.

'2. An electric switch con'iprising, a vessel containing oil and having a high resistance portion, main contacts for closing a low i-esistance circuit around said oil vessel, and auxiliary contacts connected in series with said high resistance portion and mounted to separate in said vessel after said main contacts move out of engagement.

3. In an electric switch, the combination of a metallic vessel containing oil and comprising high resistance in thermal relation to the oil, main contacts arranged to close a low resistance circuit around said oil vessel, and auxiliary contacts in sei-ies with said high resistance, mounted to separate within said vessel and operatively related to said main contacts to remain in engagement after said main contacts are separated, whereby said high resistance is automatically included in circuit with said auxiliary contacts upon disengagement of said main contacts.

4. An electric switch comprising, a metallic oil vessel of high resistance, a fixed main contact connected to one end of said vessel, a line terminal in direct connection with said fixed main contact, a fixed auxiliary contact connected to said vessel within and at the other end thereof'. and movable main and auxiliary contacts coi'iperating with said fixed main and auxiliary contacts and operatively related to cause said auxiliary contacts to remain in engagement after said main contacts are separated.

5 An electric switch comprising, a high resistance vessel containing oil, relatively movable cooperating main contacts, one of said main contacts being connected to said vessel at one point, a line terminal in direct connection with said main contacts, relatively movable coperating auxiliary contacts mounted to separate in said vessel, one of said auxiliary contacts being connected to Said vessel at another point to include a part of said vessel in series with said auxiliary contacts, and actuating means for'operating said main and auxiliary contacts in sequence to automatically include said part of said vessel in serieswith said auxiliary contacts as the switch opens.

6. In an electric switch, the combination of two metallic oil vessels, cooperating movable and fixedv main contacts for closing a circuit around said oil vessels. line terminals in direct connection with said fixed main contacts, auxiliary contacts mounted to separate within said vessels and to include a portion of said vessels in series therewith,

and actuating means for said main and said auxiliary contacts arranged to separate said main contacts while said auxiliary contacts" directly to the line, a movable bridging member coperating with said stationary contacts to establish a low resistance path between them, fixed auxiliary contacts mounted within said oil vessels and connected thereto at a distance from said main contacts, and movable auxiliary contacts mounted on said bridging member to maintain the circuit throiigh said switch after said main contacts are disengaged, said movable and stationary contacts upon disengagement automatically including in the circuit through the-switch the resistance offered by said oil vessels.

8. In an electric switch, the combination of two vertical metallic oil vesselsof high resistance, stationary contacts mounted upon the upper end of said vessels, movable contacts coperating with said stationary contacts to close a shunt circuit to said vessels, a metallic yoke bridging said movable contacts and arranged to move said ymovable contacts into and out of engagement with said stationary contacts, and auxiliary contacts within said oil vesselsfconnected by said metallic yoke and arranged to remain closed until said movable and stationary contacts have separated, said movable and stationary contacts upon disengagement opening said shunt circuit and including automatically the oil vessels in the circuit through the switch.

9. An electric switch comprising, a vessel containing oil, relatively movable coperating contacts within said vessel at one end thereof and. se arable beneath the oil, one of said contacts eing connected to said vessel, and a line terminal connected to said vessel at the other end thereof so that the` current through said vessel at any given instant is of reverse direction from the current through said contacts therein forming a magnetic loop whereby a magnetic lield is produced around said contacts to extinguish the arc formed when said contacts separate.

10. An electric switch comprising a metallic vessel containing oil, relatively movable coperating contacts separable within said vessel beneath the oil, one of said contacts being connected to said vessel, and a line terminal so connected to said vessel that the current through the vessel as said contacts separate produces around said contacts a magnetic field for extinguishing the arc formed.

11. An electric switch comprising, a metallic vessel containing oil, relatively movable coperatin main contacts, one of said contacts Ilacing in metallic connection with said vessel at one end thereof, and relatively movable coperating auxiliary contacts mounted within said vessel, one of said auxiliary contacts being in metallic connection with said vessel at the other end thereof, said auxiliary contacts remaining in engagement after said maincontacts separate and receiving a current flow at any given instant of reverse direction from the current flow in said vessel, thereby forming a magnetic field around said contacts strong enough to extinguish the arc formed when said auxiliary contacts are finally separated.

12."l In an electric switch, the combination of a metallic vessel containing oil, main contacts mounted outside and at one end of said vessel, and auxiliary contacts mounted within and'I at the other end of said vessel remaining in engagementafter said main contacts separate, said auxiliary contacts forming with Said vessel a magnetic loop whereby the tlow of current in said auxiliary contacts is in a reverse direction at any given instant from that of the current in said vessel.

In witness whereof, I have hereunto set my hand this 17th day of June, 1913.

ERNEST H. JACOBS.

Witnesses:

BENJAMIN B. HULL, HELEN ORFolm. 

